Direct TCP/IP connections in P2P apps

Question

From a Joel\'s post on Copilot:

Direct Connect! We’ve always done everything we can to make sure that Fog Creek Copilot can connect in any netw

Answer 1

I believe the simple version is that they drop the server connection and replace it with the P2P connection.

Something along the lines of:

1. Machine1 connects to copilot's servers.
2. Machine1 connects to copilot's servers.
3. Machine1 connects to copilot's servers.
4. Machine2 subsequently connects, and they begin screen sharing.
5. Machine2 opens a port intended for Machine1 to connect to.
6. Machine1 tries to connect to the now open port on Machine2.

If this connection is established:

1. The connection to copilot's servers is severed.
2. Data is instead transfered over the direct (P2P) connection between the two machines.